function count(){
    var oSpanB = document.querySelectorAll(".countdown")[0];
    var oSpan = oSpanB.getElementsByTagName('span');
    var date = new Date();
    var date2 = new Date("2022-9-9 17:25:00");
    var ss = Math.floor((date2-date)/1000);
    var hour = Math.floor(ss/3600%24);
    var min = Math.floor(ss/60%60);
    var s = Math.floor(ss%60);
    oSpan[0].innerHTML =hour;
    oSpan[1].innerHTML = min;
    oSpan[2].innerHTML = s;
    if (ss <= 0) {
        clearInterval(timer);
        oSpan[0].innerHTML ="秒杀";
        oSpan[1].innerHTML ="已经";
        oSpan[2].innerHTML ="结束";
    }
}
count();
var timer = setInterval(count,1000);